Implanted infusion pumps deliver therapeutic drugs to a patient according to a computer program executed by a processor that is programmed with drug dosing parameters. Some infusion pumps use a microprocessor to control a small, positive displacement pump according to programming instructions delivered to the microprocessor through an RF programming link so as to permit the implantable pump to be remotely programmed and operated. Other infusion pumps use compressed-gas propellants instead of a pump to deliver a drug.
Most medical devices, including infusion pumps, are specified to be stored in a particular not-to-be-exceeded temperature range. Storage temperatures outside the manufacturer's specified storage temperature range can damage implantable infusion pumps and for this reason, precautions are normally taken to insure that an implantable infusion pump is not inadvertently subjected to adversely high or low temperatures. Monitoring a pump's temperature over time would provide a mechanism by which damaging temperature extremes could be identified prior to implantation.
In addition, a pump that includes a mechanism by which the pump's temperature can be monitored might provide drug-delivery performance improvements. The flow characteristics of mechanical pumps are often temperature sensitive. Temperature compensation of undesirable flow changes can be achieved using the electrical temperature signal to adjust the flow via the internal controller.
Furthermore, monitoring patient temperature by an infusion pump, either remotely, for example at the distal end of a catheter connected to the pump, or at the pump, might allow for drug therapy delivery to be modified according to the patient's measured temperature, improving the effectiveness of the therapy.